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Geothermal power entering atmosphere?

  1. Nov 10, 2009 #1
    Hello,

    I am hoping someone on here can help me find a source for a science question I have. How much power enters the Earth's atmosphere from the Earth itself [Geothermal power]? I was reading a discussion on another website, where someone was asking about the Global Warming effect of proposed Space Solar Power (i.e. Space Solar Satellites, Dyson Cloud). The person was reasoning that such satellites are 'importing' energy into the Earth system that normally would have passed by the Earth, and on into deep space.

    My reply to the person was comparing the difference in scale between the proposed 1gW satellite, vs the 174pW of power from the Sun which is already entering the Earth's atmosphere (though, granted, some of that is reflected back to space, currently, without causing any actual warming). But, the difference in scale is so enormous, it seems reasonable that a few of those satellites would have, basically, no effect on Global Warming.

    But, as I was thinking about my answer, it occured to me that the Sun wasn't the only source of heating of the Earth's atmosphere - there is also, constantly, energy being radiated from the Earth's crust - geothermal energy, from the core of the earth, and also from, I believe, natural radioactive decay of elements in the Earth.

    I tried Google, but couldn't find any answer on how much energy the Earth itself contributes to the Atmosphere (or at least, *potentially* contributes - some of that thermal energy would, I assume, be in the form of Infrared radiation, which, as long as you don't have too much greenhouse effect in the atmosphere, can theoretically just radiate out into space)?
     
  2. jcsd
  3. Nov 19, 2009 #2
    Yes of course the Earth's core emits energy. How much im not certain but it is very insignificant to the system. Think about any night in winter time, dont know where you live but anyways, if it was really significant the ground would be warmer than it usually is due to the Earth's crust. The sun is probably responsible for at least 90% of all the energy on earth. Which is a gigantic amount. And those satelites wouldnt make global warming worst, it will probably improve it because that energy wasnt made from burning fossil fuels.
     
  4. Nov 19, 2009 #3

    mgb_phys

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    Heat output from the earth's core is 10^13 watts not exactly tiny but pretty insiginifcant compared with the solar input of 1.7 x 10^17 watts
     
  5. Nov 19, 2009 #4
    Thanks mgb, you seem to be in alot of my conversations ha ha. But what he said sounds right. The sun puts in over a 1000 times more than the earths core.
     
  6. Nov 21, 2009 #5
    Thanks for the replies, guys, especially mgb. Do you have a citation/source for that figure (10^13 for core power output)?

    I agree that the power from the Earth is pretty miniscule compared to the Sun - I expected it to be, but I was just curious was all. Mainly, when I was replying to that other guy, it occured to me that, however small the amount is in any given area, the Earth (including oceans) must put off, globally, some measurable amount of power.

    Thanks!
     
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